Phonographic apparatus



Oct. 28, 1 941. R. F. BRADY ETAL 2,260,289

PHONOGRAPHI C APPARATUS Filed March 7, 1939 2 Sheets-Sheet 1 Get. 28, 1941. BRADY ETAL 2,260,289

PHONOGRAPHI C APPARATUS Filed March '7, 1959 2 Sheets-Sheet 2 31wcntor5 new Oct. 28, 1941 Weathers, Audubon, N. J., assignors to Radio Corporation of America, a corporation of Dela.-

ware

Application March 7, 1939, Serial No. 260,282

9 Claims.

This invention relates to phonographic apparatus, and more particularly to the turntable driving mechanism, the principal object of the present invention being to provide a novel driving mechanism for the turntable by means of which it may be driven at any selected one of several different speeds.

Another object of our invention is to provide improved phonograph turntable driving mechanism by means of which the angular velocity of the turntable may be easily and quickly changed from one speed to another at will.

Still another object of our invention is to provide improved phonograph turntable driving mechanism as aforesaid which is simple in construction, which is easy to assemble and to apply to existing phonographs, and which is economical of manufacture.

In accordance with our invention, we provide a driving motor the shaft of which is formed with two pulleys or driving surfaces of different diameters. A rubber tired roller acting as a coupling idler between the motor shaft and the periphery of the turntable is arranged to be moved into engagement with the turntable periphery and either one or the other of the motor shaft pulleys. Preferably, also, the member which is employed to move the coupling idler into and out of engagement with the turntable periphery and the motor shaft is also arranged to control a switch in the circuit of the motor whereby, when the idler is' moved away from engagement with the motor shaft and the turntable periphery, the motor circuit is automatically broken, and when the idler is returned to torque transmitting positiomthe motor circuit is again automatically completed.

The novel features that we consider characteristic of our invention are set forth with particularity in theappended claims. The invention itself, however, both as to its organization and method of operation, together with additional objects and advantages thereof, will best be understood from the following description of one Figure 2 is a similar, fragmentaryview, but.

showing the coupling idler in position to drive the turntable at a relatively high speed, for example 78 R. P. M., I

Figure 3 is a side elevation with the parts corresponding to the position shown in Fig. 1,

Figure 4 is a similar fragmentary view. with the parts corresponding to the position shown in Fig. 2,

Figure 5 is a detailed view taken along the line V-V in Fig. 1,

Figure 6 is a sectional view taken on the line VI-VI of Fig. 1, and

Figure '7 is a diagrammatic view illustrating a further application of'our invention in transmitting torque to the turntable.

Referringmore particularly to the drawings,

wherein similar reference characters designate.

corresponding parts throughout, there is shown a motor board I to which is secured a, motor plate 3 carrying a motor 5. The motor plate 3 is provided with an opening 3a through which extends the motor shaft 1, the latter being formed with a relatively small diameter Ia at its upper extremity and a relatively large diameter lb immediately below the portion Ia. Above the motor board I is mounted a turntable 9 in conventional manner.

Fixed to the motor plate 3 is a post I I on which is pivotally carried a supporting lever I3, a tubular member I5 which is rotatably and slidably mounted on the post II resting on a collar I4 formed on the lever I3. A coil spring I! surrounding the post II constantly urges the lever I3 and the tubular member l5 to an elevated position, a pin I9 secured to the post ll cooperating with a bayonet slot 2| in the tubular member I5 to limit the movement of the member I5 on the post II.

Pivotally mounted on the lever I3 is another lever 23 on the free end of which is rotatably mounted a rubber tired friction wheel 25 which acts as a coupling idler betweenthe shaft 1 of the motor and the periphery of the turntable 9. The lever I3 has a pin 21 thereon which fits up through an opening 29in the lever 23 to limit movement of the lever 23 with respect to the lever I3. A coil spring 3|, one end of which is secured to a downwardly extending lug 33 on the lever I3 and the other end of which is secured to an upwardly extending post 35 on a control lever 31 which is also pivotally mounted on the post I I as clearly shown in Fig. 3, serves to constantly bias the lever I3 and the parts carried thereby clockwise about the post II, as viewed in Fig. -1. However, the lever 23' and the friction wheel 25 carried'thereby are free to float on the lever I3 within the limits determined by the pin 21 and the opening 29. These limits are wide enough 1 'ity of the slot 2|.

to permit the friction wheel 25 to freely center itself between the periphery of the turntable 8 and the motor shaft I so that when in torque transmitting position. the friction wheel 25 can become wedged in between the shaft I and the I turntable 9, the pin 21 being then free from enon the lever li so that, when the control lever 31 is moved counter-clockwise about the post j II, the member 4| will effect counter-clockwise 1o veniently manipulated. The'control lever 31 also has an upwardly extending member 4| thereon which is adapted to engage a toe [3a 1 movement of the lever l3 as well. This will cause 1 the coupling idler 25 to be moved away from the motor shaft I and the periphery of the turntable 9. To drive the turntable at 33% R. P. M.,

the cylindrical sleeve I5 is permitted to remain 1 31 is moved to its extreme clockwise position, it will automatically move the switch lever 41 to a position to close the circuit to the motor and thereby automatically eifect rotation of the motor shaft I once more. This arrangement is included as a safety feature to insure removal of the friction roller ll from engagement with the turntable 9 and the shaft 1 when the apparatus is shut down so as to preserve the correct contour of the rubber rim on the friction wheel 25. I

From the foregoing description, it will be apparent to those skilled in the art that we have provided a novel and very simple turntable driving mechanism for phonographs. Such a driving mechanism will drive the turntable at a very uniform and accurate speed. To further insure in its most elevated position as shown in Fig. 3, 1

with the pin l9 engaging'the lowermost extremcontrol lever 31 is again moved clockwise about the post II, the friction wheel will eventually be brought into engagement with the small diameter portion 1a of the motor shaft 1 and the periphery of the. turntable being free to do so tion. At such time, the cylindrical sleeve l5 may because of its floating mounting on the lever lit. The spring 3| insures firm contact between the friction wheel 25 and the shaft portion la, as well as with the periphery of the turntable, by reason of the pull which it exerts on the lever 23 through its pivotal mounting pin 24 on the lever l3. An over-center spring 43 having one end connected to'a downwardly extending post 45 on In this position, when the the control lever 31 and its other end connected to an upwardly extending post 46 on the motor plate '3 serves to releasably lock the control lever 31 in either one or the other of its extreme posi- 1 tions, as above described.

when it is desired to drive the turntable 9 at 78 R. P. M., the control lever 31 is again moved clear of the periphery of the large diameter por- 3 tion lb of the motor shaft] in a vertical direc- 5 be pressed downwardly as far as it will go against 1 the action of the spring I! and then turned slightly clockwise, as viewed in Fig. 1, so that the portion 2la of the slot 2| will be brought into engagement with the pin l9. This brings large diameter portion 1b of the motor shaft, and when the control lever 31 is next returned to the position shown in Fig. 2, the coupling idler 25 will be in engagement with the portion lb and with the turntable periphery under conditions similar to those described above R.P. M. drive.

The circuit to the motor 5 is preferably cona'forked operating lever 41. 'A pin 49 on the moved to its extreme counter-clockwise position, the switch lever. is caused to move to a position motor circuit, whereupon the motor shaft I ceases rotation. However, when the control lever trolled by means of a toggle switch 48 which has,

5 the friction wheel 25 down to the level of the for the 33% control lever'3'l extends down through an opening 5| in the motor plate 3 and is received by j the'f orked lever 41. Thus, when the lever 31 is to open theswitch 48 and thereby break the uniformity of speed of the turntable 9 where, as occasionally happens, there may be slight fluctuations in speed arising in the motor, two or more driving units, as described above, may be connected to the turntable, as shown diagrammatically in Fig. 7. With such an arrangement, it is evident that greater uniformity of speed will .be insured because it is exceedingly remote that the same sources of speed fluctuations will be present in all of the driving units and at the same time.

Although we have shown and described but a single embodiment of our invention, it should be evident that many variations thereof are possible. We, therefore, do not wish tobe limited except insofar as is made necessary by the prior art and by the spirit of the appendedclaims.

We claim: I

1. In phonographic apparatus, the combination of a motor having a driving shaft provided'with portions of different diameters, a turntable, and a friction wheel adapted to transfer torque from said shaft to said turntable, said friction wheel being mounted for movement into engagement withthe periphery of said turntable and any one of said shaft portions at will whereby to drive said turntable at any preselected one of a plurality of speeds.

2. Inphonographic apparatus, the combination of a motor having a driving shaft provided with portions of different diameters, a turntable, a friction wheel adapted to transfer torque from said shaft to said turntable, and'means for holding said friction wheel in engagement with the periphery of said turntable and any one of said shaft portions whereby to effect a driving coupling between said shaft and said turntable.

3. In phonographic apparatus, the combination of a motor having a shaft provided with portions of different diameters, a turntable, a friction wheel mounted for movement into engagement with the periphery of said turntable and anyone of said shaft portions, means for adjusting said friction wheel to engage any selected one of said shaft portions, and means for bringing said friction'wheel into engagement with said selected shaft portion and said turntable periphery.

4. In phonographic apparatus, the combination of a motor having a shaft provided with portions of different diameters, a turntable, a friction wheel mounted for movement into engagement with the periphery of said turntable and any one of said shaft portions, means for adjusting said friction wheel to engage any selected one of said shaft portions, means for" bringing said friction wheel into and out of'engagement with said selected shaft portion'and said turntable periphery at will, and means for releasably lockingsaid.

friction wheel in either of said last named positions.

5. The invention set forth in claim 4 characterized by the addition of means for insuring firm engagement between said friction wheel and both said motor shaft and said turntable periphery.

6. The invention set forth in claim 4 characterized by the addition of a spring member for constantly biasing said friction wheel toward both said motor shaft and said turntable periphery.

7. In phonographic apparatus, the combination of an electric motor having a shaft provided with portions of different diameters, a turntable, a friction wheel mounted for movement into engagement with the periphery of said turntable and any one of said shaft portions, means for adjusting said friction wheel to engage any selected one of said shaft portions, control means for bringing said friction wheel into and out of engagement with said selected shaft portion and said turntable periphery at will, switch means in circuit with said motor, and means associated with said control means for opening and closing said switch.

8. In .phonographic apparatus, the combination of a motor having a driving shaft provided with portions of different diameters, a turntable, a. supporting member, a rotatable friction wheel floatingly carried by said supporting member, said supporting member being mounted for movement from and to a position such that said friction wheel will engage the periphery of said turntable and said shaft, means for adjusting said supporting member to bring said friction wheel into alignment with any preselected one of said shaft portions, and control means for moving said supporting member into said position whereby said friction wheel will be brought into engagement with said turntable periphery and said preselected shaft portion.

9. The invention set forth in claim 8 characterized by the addition of means for insuring firm engagement between said friction wheel and both said turntable periphery and said motor shaft.

RAYMOND F. BRADY. PAUL WEATHERS. 

